If you've lost some of the plug that's a good sign that things might happen sooner rather than later.
My little one didn't fully engage until the last minute. I had a midwife appointment two days before and I think she was 2/5 engaged at the time and the wrong way round still but she seemed to work it out quick enough in the end.
They can't make you have an induction if you don't want to. I doubt you'll last till then anyway but if it came to that you could agree to be monitored but explain your reasons for wanting to wait a little longer for the induction. As others have mentioned already 42 weeks is still considered full term and in France I believe they don't consider intervening until after this point.
Going for a walk (waddle
) can help move things along. Sex as mentioned a) because of the stimulation and b) apparently there's something in the sperm that acts similarly to the gel stuff that they sometimes use to encourage labour.
Raspberry leaf tea (or tablet form) is supposed to help with the second stage of labour making it shorter/more effective. You can take it from 32 weeks into the pregnancy which I think you're over.
As for the position of the baby sitting on one of those inflatable gym balls is supposed to help you keep your pelvis in the right position to encourage bubs to turn properly.
The other suggestion my midwife gave me was to sit on a dinning chair the wrong way round so I was facing the back of the sit leaning forwards slightly.
I basically only used the ball to sit on instead of the sofa for the last couple of weeks.
You probably already know this seeing as you mention wanting an active birth but other than when they need to examine you try and keep off of your back while in labour.
This was something I was planning before hand to avoid but when I had a contraction while laying on my back after the exam it just felt like I was completely out of control whereas squatting or on all fours is a lot better for concentrating your energy but you'll find what works for you at the time.
Good luck!